For the uninformed, there was a report by an analyst from a financial services group, Nomura International. The end-2007 report prepared by Richard Windsor noted a severe structural integrity problem in the touch-screen technology used in the iPhone. His research pointed out that the technology was created by a Finnish firm, which had gone bankrupt and Apple bought over the rights to the technology.
The problem faced by the Finnish firm was that the technology had a serious degradation issue. Extensive use of the screen over about three to six months would cause the problem to exhibit itself as a loss of sensitivity in the touch screen. From what iPhone users have said, an iPhone screen afflicted with this problem will have one portion of it become completely unresponsive to any touch, and this problem is widely known among the iPhone community as the ‘dead strip’ problem as it usually affects a horizontal strip of the iPhone's touch screen.
Now, it has been many months since that report was published, and yet users are still complaining of such problems appearing on their iPhones. Sometimes the problem would occur much earlier, if they dropped or abused their iPhones. Some users have even tried to repair the problem by doing various software tweaks to the iPhone, like increasing the touch screen sensitivity, but to no avail. The hardware problem is so serious that there is just simply no way to repair it, except to completely replace the screen.